docs: def wpad_search_urls(subdomain_or_host, fld):
      """
      Generate URLs from which to look for a PAC file, based on the subdomain and TLD parts of
      a fully-qualified host name.
  
      :param str subdomain_or_host: Subdomain portion of the fully-qualified host name.
          For foo.bar.example.com, this is foo.bar.
      :param str fld: FLD portion of the fully-qualified host name.
          For foo.bar.example.com, this is example.com. 
      :return: PAC URLs to try in order, according to the WPAD protocol.
      :rtype: list[str]
      """
      parts = subdomain_or_host.split('.')
      search_urls = []
      for i in range(1, len(parts)+1):
          # Chop off host and move up the subdomain hierarchy.
          url = 'http://wpad.{}/wpad.dat'.format('.'.join(parts[i:] + [fld]))
          search_urls.append(url)
  
      return search_urls